[A serum lipidomic study of patients with non-alcoholic fatty liver disease]

Objective: To investigate the serum lipidomic profile in patients with nonalcoholic fatty liver disease (NAFLD), and to analyze the lipid metabolism characteristics of NAFLD. Methods: The subjects were divided into control group (23 patients) and pathologically confirmed NAFLD group (42 patients), and ultra-high-performance liquid chromatography-tandem mass spectrometry was used to measure serum lipidomic metabolites. The partial least squares-discriminant analysis (PLS-DA) model was established to analyze the differences in lipid metabolism with reference to the univariate analysis. The t-test and Mann-Whitney U test were used for data analysis. Results: A total of 239 lipids were identified and qualitative and quantitative analyses were performed. The PLS-DA model (R2 = 0.753, Q2 = 0.456) and the univariate analysis showed that 77 lipids were metabolized differentially between the NAFLD group and the control group (VIP > 1, P < 0.05), including free fatty acid, phosphatidylcholine, phosphatidylethanolamine, phosphatidylinositol, lysophosphatidylcholine, lysophosphatidylinositol (LPI), choline plasmalogen (PlsCho), ethanolamine plasmalogen (PlsEtn), ceramide (Cer), sphingomyelin, and triglyceride (TG). Compared with the control group, the NAFLD group had significant increases in monounsaturated fatty acids (increased by 39%, t = -3.954, P < 0.05) and TGs (increased by 36%, Z = -2.662, P < 0.05), mainly TGs with low numbers of carbon atoms and unsaturated bonds, while there were reductions in TGs with high numbers of carbon atoms and unsaturated bonds. In addition, compared with the control group, the NAFLD group had significant increases in the levels of LPI (increased by 223%, t = -3.858, P < 0.05) and Cer (increased by 21%, t = -2.481, P < 0.05) and significant reductions in PlsCho (reduced by 18%, t = 3.184, P < 0.05) and PlsEtn (reduced by 20%, t = 2.363, P < 0.05). Conclusion: There is a significant difference in lipid metabolism profile between NAFLD patients and healthy people, and a serum lipidomic analysis of NAFLD helps to further clarify the characteristics of lipid metabolism in patients with NAFLD.